Expandable fusion device and method of installation thereof

Abstract

The present invention provides an expandable fusion device capable of being installed inside an intervertebral disc space to maintain normal disc spacing and restore spinal stability, thereby facilitating an intervertebral fusion. In one embodiment, the fusion device includes a body portion, a first endplate, and a second endplate, the first and second endplates capable of being moved in a direction away from the body portion into an expanded configuration or capable of being moved towards the body portion into an unexpanded configuration. The fusion device is capable of being deployed and installed in both configurations.

What is claimed is: 
     
         1 . An expandable fusion device, comprising:
 a first endplate;   a second endplate;   a body portion positioned between the first and second endplates;   a translation member receivable within the body portion in between the first and second endplates, wherein the translation member includes at least three upper ramped surfaces that contact corresponding ramped portions of the first endplate and at least three lower ramped surfaces that contact corresponding ramped portions of the second endplate;   an actuation member engaged with the translation member; and   an interference nut operably attached to a rear section of the body portion and configured to minimize the risk of the actuation member being loosened prior to or during use.   
     
     
         2 . The expandable device of  claim 1 , wherein the at least three upper ramped surfaces are sloped generally in the same direction and the at least three lower ramped surfaces are sloped generally in the same direction. 
     
     
         3 . The expandable device of  claim 2 , wherein the actuation member is operatively attached to the interference nut. 
     
     
         4 . The expandable device of  claim 3 , wherein the interference nut is configured to cause drag on the actuation member. 
     
     
         5 . The expandable device of  claim 2 , wherein the body portion includes a pair of side slots each for receiving a stabilization member therein. 
     
     
         6 . The expandable device of  claim 1 , wherein the actuation member is configured to pass through the interference nut. 
     
     
         7 . The expandable device of  claim 1 , wherein the actuation member is configured to rotate and cause translation of the translation member. 
     
     
         8 . An expandable fusion device, comprising:
 a first endplate;   a second endplate;   a body portion positioned between the first and second endplates;   a translation member receivable within the body portion in between the first and second endplates, wherein the translation member includes at least three upper ramped surfaces that contact corresponding grooved portions of the first endplate and at least three lower ramped surfaces that contact corresponding grooved portions of the second endplate;   an actuation member engaged with the translation member; and   an interference nut operably attached to a rear section of the body portion, wherein the interference nut is configured to cause drag on the actuation member thus minimizing the risk of the actuation member being loosened prior to or during use.   
     
     
         9 . The expandable device of  claim 8 , wherein the at least three upper ramped surfaces are sloped generally in the same direction and the at least three lower ramped surfaces are sloped generally in the same direction. 
     
     
         10 . The expandable device of  claim 9 , wherein the actuation member is operatively attached to the interference nut. 
     
     
         11 . The expandable device of  claim 10 , wherein the interference nut is configured to cause drag on the actuation member. 
     
     
         12 . The expandable device of  claim 8 , wherein the body portion includes a pair of side slots each for receiving a stabilization member therein. 
     
     
         13 . The expandable device of  claim 8 , wherein the actuation member is configured to pass through the interference nut. 
     
     
         14 . The expandable device of  claim 8 , wherein the actuation member is configured to rotate and cause translation of the translation member.